The Number 221: Properties and MeaningsPrime Factors of 221=13x17.
221 is a Centered Square Number.
221 is a Centered 22-gonal Number.
221 is the sum of the squares of the first 3 factorials.
221 is the number of Hamiltonian Planar Graphs with 7 vertices.
221b, Baker Street, London, England is the address of Sherlock Holmes.
Aircraft: Boeing 221.
Firearms: the .221 Remington Fireball pistol cartridge.
U.S. Route 221 in Virginia.
The Year 221 ADIn the year 221 AD Liu Bei, Chinese warlord and descendant of the royal family of the Han Dynasty, proclaimed himself emperor. The Shu Han Kingdom was established.